1. Nitrogen Cycle
Nitrogen Cycle

2. What is Nitrogen ?
• nitrogen is a colorless, odorless, tasteless, and mostly inert
diatomic gas
• nitrogen compounds are versatile organics
• All life requires nitrogen-compounds, e.g., proteins and
nucleic acids.
• Air, which is 78% nitrogen gas , is the major reservoir of
nitrogen.
• Plants must secure their nitrogen in "fixed" form
• Animals secure their nitrogen (and all other) compounds from
plants (or animals that have fed on plants).
• one of the primary nutrients critical for the survival of all
living organisms.

3. What is nitrogen cycle?
• is the process by which nitrogen is
converted between its various chemical
forms.
Four processes participate in the cycling of
nitrogen through the biosphere:
 Nitrogen Fixation
 Decay
 Nitrification
 Denitrification

4. Nitrogen Fixation
• nitrogen must be processed, or "fixed", to be
used by plants.
• plants and animals are not able to use nitrogen
gas in that form. For nitrogen to be available to
make proteins, DNA, and other biologically
important compounds, it must first be
converted into a different chemical form.

5. Ammonification/ Decay
• convert the organic nitrogen within the remains
back into ammonium

6. Nitrification
• Ammonia by decay converts it to Nitrates
• It is important for the ammonia to be
converted to nitrates because accumulated
nitrites are toxic to plant life.

7. Dennitrification
• Denitrification reduces nitrates to nitrogen
gas, thus replenishing the atmosphere

8. Importance of Nitrogen Cycle
• Nitrogen is one of the primary nutrients critical
for the survival of all living organisms.
Although nitrogen is very abundant in the
atmosphere, it is largely inaccessible in this
form to most organisms
• Nitrogen is arguably the most important
nutrient in regulating primary productivity and
species diversity in both aquatic and terrestrial
ecosystems
• Clearly illustrates the key role played by
microorganism in a well-balance ecosystem.